https://mastodon-analytics.com/ did not update for some days, but today there are 2.1M active users
I just checked, there are 97 Signal contacts on my phone.
Edit: It’s all persons I really know
This is also an interresting read: https://www.engadget.com/2019-01-31-sex-censorship-killed-internet-fosta-sesta.html
PDF is an Open Standard, the problem is that every site tells you that you can only open it with a program from Adobe.